Hair treatment method

ABSTRACT

The invention concerns a method for treating hair keratin fibers to provide them with new appropriate properties, comprising the following steps: reducing the sulphur bonds of hair keratin to generate only at the surface of the fibers at a depth less than 10 μm. reactive sites and in fixing covalently on said reactive sites at least one active compound for providing the hair keratin fibers with new appropriate properties, said active compound containing at least a reactive function capable of reacting with said reactive sites formed at the keratin fiber surface. This method is applicable to the treatment of fibrous or non-fibrous keratin substances of human or animal origin.

The present application is a divisional of application Ser. No.09/380,459 filed Nov. 22, 1999 which is U.S. Pat. No. 6,361,767 which inturn is a 371 national phase application of PCT/FR98/99429 filed Mar.4,1998.

The present invention relates to a novel method for treating hair toendow it with novel appropriate properties.

As is well known in the art, the cosmetic qualities of hair can beimproved by applying a variety of compositions based on one or moreactive compounds to endow it with a variety of properties such as, forexample, shine, easy disentangling, volume, hold, suppleness, vitalityor softness.

To be properly effective, the active compounds of such compositionsshould, of course, have a certain affinity for the keratinous fibres ofthe hair, and should also have good persistence.

In other words, such active compounds should as far as possible remainfixed to the hair in a quantity sufficient to endow it with the desiredproperties.

However, since such active principles are not irreversibly fixed but areonly fixed by adsorption, they are gradually eliminated by desorptionduring successive washes using shampoo.

To improve the persistence, studies have primarily been based ontreatments which tend to cause a large proportion of the activeprinciples to penetrate into the fibres, either by selecting such activeprinciples which have a particular affinity for the fibres, or bymodifying the fibres to increase their porosity and encouragepenetration.

Thus coloration of hair keratin fibres is known to be improved bycarrying out coloration simultaneously with permanent-waving. Reductionof the disulphide bonds of the keratin at depth permits the colorant topenetrate deeper and thus produces a certain durability of coloration.

This type of treatment, however, is not without serious disadvantages asit causes substantial degradation not only of the surface condition ofthe keratinous fibres, but also of their intrinsic mechanicalproperties.

As a result of a great deal of research in this field with a regard toremedying the disadvantages encountered until now, it has surprisinglyand unexpectedly been shown that excellent results could be obtainedwhen fixing active compounds to keratinous hair fibres without themsuffering detrimental degradation. This has been achieved by limitingreactive site formation to only the surface of the keratinous hairfibres using a reducing agent employed under conditions and inproportions such that reactive sites are only generated at the peripheryof the surface of the keratinous fibres.

It has actually been shown that the creation of reactive sites only onthe surface is sufficient, and that they are remarkably reactive, toresult in good fixing of a variety of active compounds by means ofcovalent bonds, without the original mechanical properties of the hairbeing substantially modified.

Thus the subject of the present invention is a novel method for treatingkeratinous hair fibres with a view to endowing them with novelappropriate properties, the method comprising steps consisting inreducing the disulphide bonds of the keratin with a view to generatingreactive sites only on the surface to a depth of less than 10 μm and tocovalently fix to said reactive sites at least one active compoundcapable of endowing the keratinous hair fibres with novel appropriateproperties, said active compound comprising at least one reactivefunction capable of reacting with said sites formed at the surface ofthe keratinous fibres.

In accordance with the invention, the treatment method can be carriedout either in two separate steps, namely reducing the disulphide bondsof the keratin in a first step, and fixing the active compound bycovalent bonds in a second step, or in a single step consisting insimultaneously reducing the disulphide bonds of the keratin and fixingthe active compound.

In a further aspect, the treatment method of the invention envisagesfirst applying the active compound to the keratinous hair fibres andthen reducing the disulphide bonds of the keratin.

The essential characteristic of the method of the invention is to formreactive sites only on the surface of the keratinous hair fibres using areducing composition.

A variety of conventional reducing agents can be used to this end, buttheir nature and concentration and method of application must be suchthat reactive sites are only generated on the surface of the keratinoussubstrate.

In other words, the reducing composition must not react beyond a depthof 10 μm, preferably not beyond an average depth of 4 to 5 μm,approximately corresponding to its cuticle.

These are, of course, average values which can vary depending on thetype of treatment and which can thus be substantially lower orsubstantially higher than those indicated.

The reactive sites generated at the surface of the keratinous fibres arenucleophilic in nature and are essentially thiol functions.

In accordance with the invention, the reduction can be such that itgenerates between 0.1% and 5% by weight of cysteine with respect to thetotal amino acids of the keratinous fibres, preferably between 0.1% and2% by weight.

Non limiting examples of hair keratin reducing agents which can be citedare:

-   -   thiols such as thioglycolic acid, thiolactic acid,        3-mercaptopropionic acid, thiomalic acid, 2,3-dimercaptosuccinic        acid, cysteine, N-glycyl-L-cysteine, L-cysteinylglycine and        their esters and salts, thioglycerol, cysteamine and its C₁-C₄        acylated derivatives, N-mesylcysteamine, N-acetylcysteine,        N-mercaptoalkylamides of sugars such as        N-(2-mercaptoethyl)gluconamide, pantetheine, the        N-(mercaptoalkyl)-ω-hydroxyalkylamides described in patent        application EP-A-0 354 835, the N-mono or N,N-dialkyl-4-mercapto        butyramides described in patent application EP-A-0 368 763, the        aminomercaptoalkylamides described in patent application EP-A-0        432 000, the derivatives of N-mercaptoalkyl)succinamic acid and        N-(mercaptoalkyl)succinimides described in patent application        EP-A-0 465 342, the alkylamino mercaptoalkylamides described in        patent application EP-A-0 514 282, the azeotropic mixture of        2-hydroxypropyl thioglycolate and (2-hydroxy-1-methyl)ethyl        thioglycolate described in patent application FR-A-2 679 448,        the mercaptoalkylaminoamides described in patent application        FR-A-2 692 481, and the N-mercaptoalkylalkanediamides described        in patent application EP-A-0 653 202;    -   hydrides such as sodium or potassium borohydride;    -   alkali or alkaline-earth metal sulphites or bisulphites;    -   phosphorus derivatives such as phosphines or phosphites;    -   hyperbranched polymers and dendrimers carrying terminal thiol        functions, such as those described in patent application FR 97        04085 and having formula (I):        where:    -   Y represents an oxygen atom or an NH group;    -   A represents a linear, branched or cyclic, saturated or        unsaturated C₁-C₁₂ alkane di-yl group;    -   this alkane di-yl group can optionally be interrupted by one or        more heteroatoms, such as O or N;    -   this alkane di-yl group can optionally be substituted by:        -   an amino function: —NH₂, optionally in the form of a salt of            a mineral or organic acid;        -   an acylamino function: —NH—COR, where R represents a linear,            branched or cyclic, saturated or unsaturated C₁-C₁₀ alkyl            group;        -   a carboxylic acid function;        -   a C₁-C₁₀ ester function;    -   X represents a nucleophilic group.

In a particular preferred embodiment of the method of the invention, thereducing agent is a phosphine or a salt of a phosphine and a mineral ororganic acid.

Among the phosphines which have provided particularly advantageousresults as regards the formation of reactive sites on the surface ofkeratinous hair fibres, mention may be made of those with formula:

where:

-   -   R₁, R₂ and R₃, which are identical, represent:        -   (a) —(CH₂)_(n)—CH₃        -   (c) —(CH₂)_(n)—COOR        -   (d) —(CH₂)_(n)—CONRR′ and        -   (e) —(CH₂)_(n)—NRR′            -   n=1 to 3            -   m=0 or 1 to 3            -   R and R′, which may be identical or different, represent                a hydrogen atom or a linear or branched C₁-C₄ alkyl                radical, and salts of said compounds with formula (I).

Salts of phosphines with formula (I) which can be cited includehydrochlorides, hydrobromides, sulphates, citrates, oxalates andacetates.

Phosphines with general formula (I) which are particularly preferred andwhich can be cited include tris(2-carboxyethyl)phosphine andtris(hydroxymethyl)-phosphine which have the particular advantage notonly of being odourless and water-soluble but also of being stabletowards oxygen.

Phosphines with general formula (I) are known and have been described inparticular in patents U.S. Pat. No. 3,754,035 and U.S. Pat. No.3,489,811, as well as in EP-A-0 339 212 and in the publication by J. A.Burns et al., J.O.C. 56, 2648-2650 (1991).

The reducing agent is preferably used in aqueous solution underconditions such that its penetration is low to limit the reduction ofdisulchide bonds to the surface only.

When using a thiol such as thioglycolic acid, for example, itsconcentration is generally in the range 0.05 to 0.5 M, the pH of theaqueous solution is preferably in the range 6.5 to 9, and the contacttime is generally in the range 1 to 10 minutes and preferably in therange 2 to 5 minutes, the pH being adjusted using an agent selected, forexample, from: aqueous ammonia, monoethanolamine, diethanolamine,triethanolamine, 1,3-propanediamine, an alkaline or ammonium carbonateor bicarbonate, an organic carbonate such as guanidine carbonate, or analkaline hydroxide, or advantageously using a polyquaternary ammoniumhydroxide such as:

-   (a) homopolymers comprising units with the following formula (III)    as the principal constituent of the chain:    -   where:    -   k and t are equal to 0 or 1, the sum k+t being equal to 1;    -   R₄ and R₅ each independently represent an alkyl radical        containing 1 to 22 carbon atoms, a hydroxyalkyl radical where        the alkyl group preferably contains 1 to 5 carbon atoms, or an        amidoalkyl radical where the alkyl group preferably contains 1        to 5 carbon atoms;    -   or R₄ and R₅, together with the nitrogen atom to which they are        attached, can represent heterocyclic radicals such as piperdyl        or morpholinyl radicals;    -   R₆ represents a hydrogen atom or a methyl radical;-   (b) quaternary diammonium polymers containing repeat units with    formula (IV):    -   where:    -   R₇, R₈, R₉ and R₁₀, which may be identical or different,        represent aliphatic, alicyclic or arylaliphatic radicals        containing 1 to 20 carbon atoms or C₁-C₅ lower hydroxyaliphatic        radicals, or R₇, R₈, R₉ and R₁₀, taken together or separately,        form heterocycles with the nitrogen atoms to which they are        attached, optionally containing a second heteroatom other than        nitrogen, or R₇, R₈, R₉ and R₁₀, represent a linear or branched        C₁-C₆ alkyl radical substituted by a nitrile, ester, acyl, amide        or —COOR₁₁—Q or —CO—NH—R₁₁—Q function where R₁₁ is an alkylene        and Q is a quaternary ammonium group;    -   A and B represent linear or branched, saturated or unsaturated        polymethylene groups containing 2 to 20 carbon atoms which may        contain, bonded to or interposed in the main chain, one or more        aromatic ring(s), one or more oxygen or sulphur atom(s), or        sulphoxide, hydroxyl, quaternary ammonium, ureido, amide or        ester groups;    -   A, R₇ and R₈ can further form a piperazine ring with the two        nitrogen atoms to which they are attached; further, if A        represents a linear or branched, saturated or unsaturated        alkylene or hydroxyalkylene radical, B can also denote a        —(CH₂)_(n)—CO—D—OC—(CH₂)_(n)— group where D represents:    -   (i) a glycol residue with formula —O—Z—O— where Z represents a        linear or branched hydrocarbon radical, or a        —(CH₂—CH₂—O)_(x)—CH₂—CH₂— or        —[CH₂—CH—(CH₃)—O]_(y)—CH₂—CH—(CH₃)—where x and y represent an        integer from 1 to 4 corresponding to a defined and unique degree        of polymerization, or any number from 1 to 4 corresponding to a        mean degree of polymerization;    -   (ii) a bis-secondary diamine residue such as a piperazine        derivative;    -   (iii) a bis-primary diamine residue with formula —NH—Y—NH— where        Y represents a linear or branched hydrocarbon radical or the        divalent radical —CH₂—CH₂—S—S—CH₂—CH₂—;    -   (iv) a ureylene group with formula —NH—CO—NH—;    -   (v) polyquaternary ammonium polymers constituted by units with        formula (V):        -   where:        -   R₁₁, R₁₂, R₁₃ and R₁₄, which may be identical or different,            represent a hydrogen atom, a methyl, ethyl, propyl,            β-hydroxyethyl, β-hydroxypropyl, β-hydroxypropyl or            —CH₂—CH₂—(O—CH₂—CH₂)_(q)—OH radical, q being an integer from            0 to 6 and R₁₁, R₁₂, R₁₃ and R₁₄ not simultaneously being a            hydrogen atom;        -   B₁ represents a linear or branched, saturated or unsaturated            polymethylene group containing 2 to 20 carbon atoms and            containing, bonded to or interposed in the main chain, one            or more aromatic ring(s) or one or more oxygen or sulphur            atom(s), or sulphoxide, sulphone, disulphide, amino,            alkylamino, hydroxyl, quaternary ammonium, ureido, amide or            ester groups; B₁ preferably represents a radical with            formula            —CH₂—CH₂—O—CH₂—CH₂—,        -   p represents an integer from about 1 to 6;        -   E can be zero or represent a —(CH₂)_(r)—CO— group where r            represents a number equal to 4 or 7.

Of these polymers with formulae (II), (III) and (IV), those which arepreferably used are selected from:

-   -   the compound with formula (III) where R₇, R₈, R₉ and R₁₀        represent the methyl radical; A represents the radical —(CH₂)₃—        and B represents the radical —(CH₂)₆—;    -   the compound with formula (III) where R₇ and R₈ represent the        ethyl radical, R₉ and R₁₀ represent the methyl radical and A and        B represent —(CH₂)₃—;    -   the compound with formula (III) where R₇, R₈, R₉ and R₁₀        represent the methyl radical and A and B represent —(CH₂)₃—;    -   the compound with formula (III) where R₇, R₈, R₉ and R₁₀        represent the methyl radical and A and B represent —(CH₂)₆—;    -   the compound with formula (III) where R₇, R₈, R₉ and R₁₀        represent the methyl radical; A represents the radical —(CH₂)₃—        and B represents the radical —(CH₂)₉—;    -   the compound with formula (III) where R₇, R₈, R₉ and R₁₀        represent the methyl radical; A represents the radical —(CH₂)₃—        and B represents the radical —(CH₂)₂—O—(CH₂)₂—;    -   the compound with formula (III) where R₇, R₈, R₉ and R₁₀        represent the methyl radical; A represents the radical —(CH₂)₃—        and B represents the radical —(CH₂)₂—O—(CH₂)₂—O—(CH₂)₂—;    -   the compound with formula (III) where R₇, R₈, R₉ and R₁₀        represent the methyl radical; A represents the radical        —(CH₂)₂—O—(CH₂)₂—and B represents the radical        —(CH₂)₂—O—(CH₂)₂—O—(CH₂)₂—;    -   the compound with formula (IV) where R₁₁, R₁₂, R₁₃ and R₁₄        represent the methyl radical; B₁ represents the radical        —CH₂—CH₂—O—CH₂—CH₂— and E represents the radical —(CH₂)₄—CO—;    -   the compound with formula (IV) where R₁₁, R₁₂, R₁₃ and R₁₄        represent the methyl radical; B₁ represents the radical        —CH₂—CH₂—O—CH₂—CH₂— and E represents the radical —(CH₂)₇—CO—;    -   the compound with formula (IV) where R₁₁, R₁₂, R₁₃ and R₁₄        represent the methyl radical; B₁ represents the radical        —CH₂—CH₂—O—CH₂—CH₂— and E has the value zero;    -   the compound with formula (II) where t=1 and k=0; R₄ and R₅        represent the methyl radical and R₆ represents a hydrogen atom.

The polyquaternary ammonium hydroxides with formulae (II), (III) and(IV) are prepared from the corresponding polyquaternary ammonium halides(the nalide being Cl⁻ or Br⁻) using methods which are known per se,namely:

-   -   either exchange with a basic resin such as IRA 400 resin, DOWEX        1×10 resin, etc., in an aqueous medium;    -   or by precipitation of the halides in the form of silver bromide        or chloride using silver oxide Ag₂O in an aqueous medium.

When a hydride such as, for example, potassium borohydride is used, itsconcentration is generally in the range 0.01 to 0.5 M, the contact timeis in the range 1 to 30 minutes, preferably in the range 2 to 15minutes, and the pH of the aqueous solution is preferably in the range7.5 to 9.5, the acidifying agent allowing the pH to be adjustedadvantageously being boric acid.

When using a phosphorus derivative such as a phosphine, itsconcentration is generally in the range 10⁻³ M to 1 M, preferably in therange 10⁻² M to 0.5 M, the contact time is generally in the range 30seconds to 1 hour, preferably in the range 1 to 30 minutes, and the pHof the aqueous solution is preferably in the range 3 to 9, moreparticularly in the range 4 to 7.

When using a hyperbranched polymer or a dendrimer carrying thiolfunctions, its concentration is generally such that the thiol titre ofthe solution is generally in the range 100 to 5000 meq/l, preferably inthe range 500 to 2000 meq/l, the contact time is generally in the range30 seconds to 1 hour, preferably in the range 1 to 30 minutes, and thepH of the aqueous solution is preferably in the range 5 to 11, moreparticularly in the range 7.5 to 10.5.

The disulphide bond reduction step is generally carried out at roomtemperature, but it can also be carried out at a temperature of lessthan 60° C.

Clearly, these different parameters concerning the concentration, pH,temperature and contact time are interdependent and clearly, dueconsideration in this respect should be given. Thus, for example, anincrease in the concentration or a rise in temperature will result in asubstantial reduction in the contact time.

When the treatment method of the invention is carried out in two steps,after reducing the disulphide bonds of the keratin in the keratinousfibres, they can be rinsed with water before fixing the active compound.

The active compounds which can be covalently fixed on the nucleophilicfunctions generated can be of a highly varied nature and their choicedepends on the desired properties. These active compounds can be used asthey are if they possess functions which are capable of forming covalentbonds with the nucleophilic functions of the keratinous hair fibres.

When the active compounds which are to be fixed do not possess suchfunctions, these are then first introduced into the active compoundusing known methods.

The term “reactive function” means a known reactive group which permitsthe formation of a covalent bond (by reaction with nucleophilicfunctions, in this instance sulphydryl functions −SH) and which thuscomprise one or more nucleofuge(s) X or one or more activated carbon(s)or bond(s). The following groups are the usual nucleofuges:

-   -   Cl, Br, F, —OSO₃M, —OSO₂ alkyl, —OSO₂ aryl, —OSO₂N(alkyl)₂,        —OR₁, SR₂, —SOR₂, —SO₂R₂, —S⁺R₂R₃, —SCN, —SCOOR₂, —NR₂R₃,        N⁺R₂R₃R₄,    -   where M represents a hydrogen atom, an alkali or an        alkaline-earth metal or an ammonium residue;    -   R₁ represents a hydrogen atom, a C₁-C₄ alkyl radical, a        substituted or unsubstituted phenyl radical, the radical PO₃H₂        and its salts, or the acetyl radical;    -   R₂, R₃ and R₄, which may be identical or different, represent a        hydrogen atom, a C₁-C₄ alkyl radical or a substituted or        unsubstituted phenyl radical.

Among the most well known reactive groups, the following can be cited:

-   -   mono- and dihalotriazines;    -   dihaloquinoxalines, dihalopyrimidines;    -   vinylsulphones or their β-halo- or β-sulpha-toethylsulphone        precursors;    -   acrylates and methacrylates;    -   acrylamides and methacrylamides;    -   maleimides and halomaleimides;    -   epoxides and aziridine derivatives;    -   oxazolinium, imadozolium or thiazolidinium groups;    -   carboxylic or sulphonic acid halides;    -   esters;    -   carbamates;    -   anhydrides;    -   isothiocyanates and isocyanates;    -   lactones;    -   azlactones with structure:        where:    -   Z represents the residue of an active compound;    -   R₁₅ and R₁₆, which may be identical or different, represent a        hydrogen atom, a C₁-C₁₂ alkyl radical, a C₃-C₁₂ cycloalkyl        radical, a C₅-C₁₂ aryl radical, a C₆-C₂₆ arenyl radical        comprising 0 to 3 heteroatoms selected from S, N and O, or R₁₅        and R₁₆ together form a carbocycle containing 4 to 12 atoms, and        n is an integer in the range 0 to 3, etc.

Among the active compounds which can be covalently fixed on thekeratinous hair fibres after reduction of the surface disulphide bonds,those which can be cited are agents which can colour them, protect themfrom external attacking factors (light, pollution, water), strengthenthem, modify their form, give them body, volume, lightness, suppleness,softness or vitality, facilitate combing or disentangling, reduce staticelectricity or increase their shine, i.e., in general any agent whichcan protect them and/or improve their appearance and/or feel.

In particular, the following active compounds can be cited by way ofexample to illustrate the invention:

-   (a) reactive colorants intended to modify hair colour, such as:    -   compounds from the REIMAZOL® range sold by DYSTAR;    -   compounds from the PROCION® range sold by ZENECA;    -   compounds from the CIBACRONE® and LANASOL® ranges sold by        CIBA-GEIGY;    -   compounds from the LEVAFIX® range sold by BAYER.        The following examples can be cited more particularly:    -   Reactive Blue 4 (C.I. 61205);    -   Reactive Black 5 (C.I. 20505);    -   Reactive Blue 19 (C.I. 61200);    -   Reactive Orange 16 (C.I. 17757);    -   Reactive Red 4 (C.I. 18105);    -   Reactive Yellow 2 (C.I. 18972);    -   Reactive Yellow 135; and    -   Reactive Red 2 (C.I. 18200).-   (b) reactive sunscreens from the benzylidenecamphor series,    para-aminobenzoic acid derivatives and esters thereof, cinnamic acid    derivatives and esters thereof, salicyl derivatives, benzophenone    derivatives, dibenzoylmethane derivatives, benzotriazole or    benzimidazole derivatives, anthranilic acid and its esters,    anthranilate or cyanoacrylate derivatives, such as those with the    following formulae, for example:-   (c) reactive shine agents, in particular silicon-containing polymers    such as polydimethylsiloxane derivatives having, for example, vinyl,    acrylic or epoxy reactive groups, etc. Examples which can be cited    are the divinylpolydimethylsiloxanes sold by HÜLS-PETRARCH under    reference numbers PS 441, PS 443, PS 445, PS 448 and PS 449.5 or the    vinylmethyl polydimethylsiloxane copolymer by the same company under    reference number PS 424;-   (d) hydrophobic reactive compounds with a C₈-C₃₀ fatty chain, such    as octadecyl methacrylate or acrylate or with a C₂ to C₁₈    perfluorinated chain, such as the FORALKYLS® AC6 and AC8, MAC6 and    MAC8 sold by ELF ATOCHEM, hexafluoropropene oxide, methyl    perfluoro-3-buteneoate, etc.

The active compound is generally present in aqueous solution in aconcentration in the range 10⁻³ to 20%, preferably in the range 10⁻² to5%, and its pH is generally in the range 2 to 10, preferably in therange 4 to 9.

The contact time necessary for formation of the covalent bonds isgenerally in the range 1 minute to 1 hour, preferably in the range 1 to30 minutes at room temperature or at a temperature of less than 60° C.

The composition containing the reducing agent and the compositioncontaining the active compound can also comprise various otheradditives.

Additives which can be cited in particular include nonionic, anionic,cationic or amphoteric surfactants, volatile or non-volatile, linear orcyclic silicones, polyorganosiloxanes, cationic polymers such as thoseused in the compositions of patents FR-A-2 472 382 and FR-A-2 495 931and of patent LU-83703, basic or acidic amino acids, peptides, proteinhydrolysates, waxes, C₃-C₆ alkanediols, C₁-C₅ lower alcohols, fattyalcohols, fatty acids, alkylene or dialkylene glycol alkyl ethers,glycerol, hydrophilic or lipophilic gelling agents, thickeners,suspension agents, opacifying agents, sequestering agents, colorants,sunscreens, fillers, pigments, odour absorbers, hair loss preventatives,anti-dandruff agents, antioxidants, vitamins, solvents, fragrances andpreservatives.

These different additives are generally present in a proportion in therange 0.01% to 20% by weight of the total composition weight.

Some examples of the hair treatment method of the invention will now begiven in order to illustrate the invention.

EXAMPLES Example 1 Method For Fixing a Colorant on Locks of Hair

A. Step for Reducing Hair Locks

Locks of natural hair containing 90% non-pigmented hair were reducedusing the following eight methods:

Method 1

A 1 g lock of natural hair was immersed for 5 minutes and at 30° C. in25 cm³ of an aqueous 0.5 M solution of tris(2-carboxyethyl)phosphineadjusted to a pH of 9 with sodium hydroxide.

Method 2

A 1 g lock of natural hair was immersed for 5 minutes at 30° C. in 5 cm³of an aqueous 0.5 M solution of tris(2-carboxyethyl)phosphine adjustedto a pH of 8.5 with sodium hydroxide.

Method 3

A 1 g lock of natural hair was immersed for 25 minutes at 30° C. in 5cm³ of an aqueous 0.1 M solution of tris(2-carboxyethyl)phosphineadjusted to a pH of 8.5 with sodium hydroxide.

Method 4

A 1 g lock of natural hair was immersed for 5 minutes at 30° C. in 25cm³ of an aqueous 0.1 M solution of sodium borohydride adjusted to a pHof 8.5 with boric acid.

Method 5

A 1 g lock of bleached hair (alkaline solubility=20%) was immersed for 5minutes at 30° C. in 30 cm³ of an aqueous 0.74 M solution ofthioglycolic acid adjusted to a pH of 8 withpoly[(dimethyliminio)-1,3-propanediyl (dimethyliminio)-1,6-hexanediyl]dihydroxide.

Method 6

A 1 g lock of natural hair was immersed for 5 minutes at 30° C. in 30cm³ of an aqueous 1 M solution of L-cysteine containing 7.8 g ofpoly[(dimethyliminio)-1,3-propanediyl (dimethyliminio)-1,6-hexanediyl]dihydroxide, adjusted to a pH of 9 with aqueous ammonia.

Method 7

A 0.1 g lock of natural hair was immersed in 1 ml of an aqueous solutioncontaining a dendrimer carrying thiol functions, the preparation ofwhich is given below (thiol titre: 1340 meq/l), at a spontaneous pH, for30 minutes at 30° C.

Preparation of the Dendrimer

540 μl of γ-thiobutyrolactone (i.e., 1 equivalent, calculated withrespect to the entirety of the primary amine functions) were added to 2g of an aqueous 55.7 g/100 g solution of dendrimer sold by DENDRITECHunder the name PAMAM STARBURST with a generation 1 ethylenediamine core(8 NH₂ functions at the surface) diluted in 2 ml of water, in an inertatmosphere at room temperature. The medium, which was initiallyheterogeneous, rapidly became homogeneous (1 hour). After 48 hours'stirring, only traces of γ-thiobutyrolactone were detected in themedium. It was washed 3 times with 10 ml of diethyl ether, then nitrogenwas bubbled through the aqueous phase thus obtained to eliminate alltraces of ether.

The aqueous solution thus obtained was analysed by NMR. It was confirmedthat all of the initial primary amine functions were in the form of—NH—CO—(CH₂)₃—SH.

The active matter content in this aqueous phase was 37.71 g/100 g.

Molar mass of synthesized product: 2247 g.mol⁻¹.

Empirical formula: C₉₄H₁₇₆N₂₀O₂₀S₈.

Method 8

A 0.1 g lock of natural hair was immersed in 1 ml of an aqueous solutioncontaining a branched polyethyleneimine polymer carrying thiolfunctions, the preparation of which is given below (thiol titre: 1220meq/l) at a spontaneous pH, for 30 minutes at 30° C.

Preparation of Branched Polyethyleneimine Polymer

1 g of polyethyleneimine with an average molecular weight MW=1200, soldby POLYSCIENCES, was diluted in 3 g of water then 482 μl ofγ-thiobutyrolactone (i.e., 6.75 molar equivalents, calculated withrespect to the average molecular weight of the polymer) was added in aninert atmosphere at room temperature. The medium, which was initiallyheterogeneous, rapidly became homogeneous (about 30 minutes). After 2hours with stirring, no more γ-thiobutyrolactone was detected in themedium. The aqueous phase gave a positive reaction after revealing withsodium nitroprusside. It was thus confirmed that some of the initialprimary amine functions were in the form of —NH—CO—(CH₂)₃—SH.

The active matter content of this aqueous phase was 34.35 g/100 g.

Molar mass of synthesized product: 1889.6 g/mol⁻¹.

After this reduction step, using methods 1 to 8, the locks were rinsedwith copious quantities of water.

Surface reduction of the disulohide bonds of the hair keratin usingmethods 1 to 8 above was demonstrated using a fluorescent probe,4-(aminosulphonyl)-7-fluoro-2,1,3-benzoxadiazole (ABD-F). This moleculereacts selectively with the keratocysteine formed, giving a fluorescentproduct. The treatment of transverse microsections of hair by a probesolution thus enabled the reduced zones of the hair to be located.

To this end, the hair reduced using methods 1 to 8 was encased in afast-setting epoxy resin. 10 μm transverse sections were obtained fromthe different encased samples produced, using a microtome.

A few drops of the following solution were then applied to the sections:2.16 mg of ABD-F in 100 ml of a pH 8 borate buffer solution containing576.8 mg of sodium lauryl sulphate, 37.2 mg of EDTA and 945.5 mg ofborax.

This was allowed to react for 30 seconds and the solution was removedusing absorbent paper. The sections were then rinsed three times withdeionized water then dried and enclosed in Canada balsam.

The fluorescence was observed using a “Diaplan” optical microscopeprovided wish a filter block to allow excitation at a wavelength λ of340-380 nm and observation in λ>430 regions. It was thus readilydetermined that reduction had occurred on the surface to a superficialdepth, and not at the interior of the hair keratin fibres.

B. Colorant Graft Step

An aqueous 10⁻² M solution of “Reactive Orange 16” (C.I. 17757) colorantwas prepared and the pH was adjusted to 9 with sodium hydroxide. Thehair lock reduced using Method 1 above was then immersed in thissolution for 30 minutes at 30° C. This operation was then repeated withthe other locks reduced using

Methods 2 to 8.

The hair locks were then rinsed with copious quantities of water andwashed several times with an aqueous 10% solution of sodium lauryl ethersulphate then dried.

Intensely orange coloured locks were thus obtained and it was confirmedthat prolonged washing and repeated shampooing did not perceptiblymodify the intensity of the coloration with respect to that initiallyobserved.

C. Comparative Study

A 1 g lock of natural hair was immersed for 30 minutes at 30° C. in 25ml of an aqueous 10⁻² M solution of “Reactive Orange 16” (C.I. 17757)colorant, the pH being adjusted to 9 using sodium hydroxide. The lockwas then rinsed with copious quantities of water and washed severaltimes with an aqueous 10% solution of sodium lauryl ether sulphate anddried.

This lock, which had not undergone prior reduction, had a very slightcoloration which was only just discernible with the naked eye and thiswas the same but to a lesser extent when the temperature and contacttime were increased.

Example 2 Method For Fixing a Fatty Chain to Hair Locks

A 1 g lock of natural hair which had previously been reduced usingMethod 1 of Example 1 was immersed in 25 cm³ of a 0.5×10⁻² M solution ofoctadecyl methacrylate in an ethanol-water (9/1) mixture and the pH wasadjusted to 9 using sodium hydroxide. After 30 minutes at 45° C., thelock was rinsed with copious quantities of ethanol then with deionizedwater and dried.

Studies carried out on the lock showed that it had a particularly markedhydrophobic nature.

Comparative Study

A 1 g lock of natural hair was immersed for 30 minutes at 45° C. in 25cm³ of a 0.5×10⁻² M solution of octadecyl methacrylate in anethanol-water (9/1) mixture and the pH was adjusted to 9 using sodiumhydroxide.

After treatment, the lock was rinsed with copious quantities of ethanolthen deionized water and dried.

A study of this lock which had not undergone the prior reduction showed,by wettability measurements, that it had a strong hydrophilic nature.This indicated that there had been no notable fixing of the fatty chain.

Example 3 Method For Fixing a Silicon-containing Polymer to Hair Locks

A 1 g lock of natural hair which had already been reduced using Method 1of Example 1 was immersed in 25 cm³ of a 1% solution ofdivinylpolydimethylsiloxane, sold by HÜLS-PETRARCH under the trade name“PS 441®”, in an ethanol-water (1/1) mixture and the pH was adjusted to8 using sodium hydroxide. After 30 minutes at 40° C., the lock wasrinsed with copious quantities of water then washed several times with a10% sodium lauryl ether sulphate solution and dried.

Using wettability measurements, it was confirmed that there had been asubstantial reduction in the hydrophilic nature of the lock, it had amuch more pleasant feel and it was more shiny.

Example 4 Method For Fixing a Sunscreen to Hair Locks

-   A. Five 1 g locks of natural brown hair which had already been    reduced using Method 2 of Example 1 were immersed in 50 cm³ of an    ethanolic 0.1 M solution of    [3-benzotriazol-2-yl-2-hydroxy-5-(1,1,3,3-tetramethylbutyl)benzyl]acrylamide    heated to 70° C. 20 drops of 0.1 M sodium hydroxide were added and    the temperature was maintained for 30 minutes.

After treatment, the locks were rinsed 5 times with 150 cm³ of ethanolthen 5 times with 250 cm³ of deionized water and dried.

-   B. Two 1 g locks of natural brown hair which had already been    reduced using Method 3 of Example 1 were immersed in 20 cm³ of a 0.1    M ethanolic solution of    [3-benzotriazol-2-yl-2-hydroxy-5-(1,1,3,3-tetramethylbutyl)benzyl]acrylamide    heated to 70° C. 8 drops of 0.1 M sodium hydroxide were added and    the temperature was maintained for 30 minutes.

After treatment, the locks were rinsed 5 times with 150 cm³ of ethanolthen 5 times with 250 cm³ of deionized water and dried.

-   C. Comparative Study

The locks obtained at A and B above and five locks of natural brown hairas a reference were exposed to artificial light in a XENOTEST 150Ssimulator for 240 hours. During exposure, the hair was sprayed withwater for 5 minutes every 15 minutes.

An examination of the locks after this exposure showed that the locksobtained at A and B, by fixing a sunscreen, exhibited far lessdegradation of their colour compared with the reference locks. Theprotective effect was clear after 48 hours of exposure and it was verymarked after 240 hours of exposure.

Example 5 Protective Effect of Sunscreens Fixed on Tinted Locks of Hair

Five 1 g locks of 90% naturally white hair which had already beenreduced using Method 2 of Example 1 were immersed in 50 cm³ of a 0.1 Methanolic solution of[3-benzotriazol-2-yl-2-hydroxy-5-(1,1,3,3-tetramethylbutyl)benzyl]acrylamideheated to 70° C. 20 drops of 0.1 M sodium hydroxide were added and thetemperature was maintained for 30 minutes.

After treatment, the locks were rinsed 5 times with 150 cm³ of ethanolthen 5 times with 250 cm³ of deionized water and dried.

The locks were then tinted using a mixture of 20 g of “MAJIREL 6.1”colorant composition and 30 g of cream oxidizing agent containing 20volumes of aqueous hydrogen peroxide solution. After leaving for 30minutes, the locks were rinsed with water then washed with shampoo.

The same treatment was also carried out on 5 locks which had previouslybeen treated using Method 3 of Example 1.

After exposure to the Xenotest under the same conditions as described inExample 4, only a very slight degradation in the colour of the locks wasnoted compared with the reference locks, i.e., tinted using only theabove colorant mixture.

Example 6 Method For Removing Yellow From White Hair

A. Hair Reduction Step

After moistening natural or permed grey hair containing 90% white hairs,the following lotion was applied for 5 minutes at room temperature in anamount of 10 g for every 3 g of hair:

Tris (2-carboxyethyl) phosphine 14.33 g Hydroxyethylcellulose 1.00 gAqueous ammonia containing qs ph 6 20% NH₃ Demineralized water qs 100.00g

The hair was then rinsed with water and squeezed drip-dry.

B. Step for Grafting Yellow-removing Composition

10 g of the following yellow-removing composition were applied for 5minutes then the hair was rinsed, washed using a standard shampoo anddried.

It was found or seen that the yellowing of the white hair had beencompletely faded out, while retaining a natural sheen.

Yellow-removing Composition:

Procion YELLOW MX-8G ® sold by 0.01 g ZENECA Procion RED MX-5B ® sold byZENECA 0.01 g Lanasol blue 3 G sold by CIBA- 0.01 g GEIGYHydroxyethylcellulose 1.00 g Lactic acid qs pH 4 Demineralized water qs100.00 g

1. Method for fixing a sunscreen or shine agent on hair keratin fibrescomprising the stops of reducing the disulphide bonds of the hairkeratin with an aqueous reducing agent solution consisting of (1)phosphines or a salt thereof and a mineral or organic acid, wherein thepH of the (1) phosphines solution is in the range 2 to 10 or (2) thiols,wherein the pH of the thiols solution is in the range 6.5 to 9 by usinga polyquaternary ammonium hydroxide said reducing agent generatingreactive sites only on the surface of said keratin fibres to a depth ofless than 10 μm and of covalently fixing on said reactive sites at leastone sunscreen or shine agent said sunscreen or shine agent containing atleast one reactive function being capable of reacting with said reactivesites formed on the surface of the keratin fibres.
 2. Method accordingto claim 1, wherein in a first step, the disulphide bonds of the keratinare reduced and then in a second step, after optional rinsing with waterthe sunscreen or shine agent is fixed.
 3. Method according to claim 1,wherein the reduction of the disulphide bonds of the keratin is carriedout simultaneously with fixing of the sunscreen or shine agent. 4.Method according to claim 1, wherein the reduction of the disulphidebonds is carried out to a depth of about 4 to 5 μm.
 5. Method accordingto claim 1, wherein the reduction is carried out to generate 0.1% to 5%by weight of cystine with respect to the total amino acids of thekeratinous hair fibres.
 6. Method according to claim 5, whereinreduction is carried out in order to generate 0.1% to 2% by weight ofcysteine with respect to the total amino acids of the keratinous hairfibres.
 7. Method according to claim 1, wherein the phosphines are ofthe formula:

R₁, R₂ and R₃, which are identical represent: (a) —(CH₂)_(n)—CH₃

(c) —(CH₂)_(n)—COOR (d) —(CH₂)_(n)—CONRR′ and (e) —(CH₂)_(n)—NRR′ n=1 to3 m=0 or 1 to 3 R and R′, which may be identical or different, representa hydrogen atom or a linear or branched C₁-C₄ alkyl radical and salts ofsaid compounds with formula (II) with a mineral or organic acid. 8.Method according to claim 7, wherein the phosphine salts with formula(II) are selected from the group consisting of hydrochlorides,hydrobromides, suiphates, citrates, oxalates and acetates.
 9. Methodaccording to claim 7, wherein the phosphines are selected from the groupconsisting of tris(2-carboxyethyl)phosphine andtris(hydroxymethyl)phosphine.
 10. Method according to claim 7, whereinthe phosphines are present in a concentration in the range 10⁻³ to 1 M.11. Method according to claim 7, wherein the pH of the reducing aqueoussolution is in the range 3 to
 9. 12. Method according to claim 1,wherein the contact time for the aqueous reducing solution with thekeratinous fibres is in the range from about 30 seconds to 1 hour, thetemperature being in the range from room temperature to a temperature ofloss than 60° C.
 13. Method according to claim 1, wherein the sunscreenor shine agent is used in an aqueous solution at a concentration in therange from about 10⁻³% to 20%, the pH of said solution being in therange from about 2 to
 10. 14. Method according to claim 1, wherein thecontact time for the aqueous solution of active colorant is in the rangefrom about 1 minute to 1 hour, the temperature being in the range fromroom temperature to a temperature of less than 60° C.
 15. Methodaccording to claim 11, wherein said pH is in the range of 4 to
 7. 16.Method according to claim 1 wherein said sunscreen is selected from thegroup consisting of a benzylidenecamphor, a para-aminobenzoic acid, anester of a para-aminobenzoic acid, a cinnamic acid, an ester of acinnamic acid, a sallcilic acid, a dibenzoylmethane, a benzotriazole, abenzimidazole, an anthranilic acid, an ester of an anthranilic acid, anantranilate and a cyanoacrylate; and said shine agent is asilicon-containing polymer.
 17. A method of treating keratinous hairfibres comprising (i) reducing disulphide bonds of the hair fibres togenerate reactive sites only on the surface of the fibres with anaqueous reducing agent solution, said reducing agent solution beingselected from the group consisting of (a) an aqueous solution comprisinga hydride present at a concentration of 0.01 to 0.5M, said solutionhaving a pH in the range of 7.5 to 9.5, (b) an aqueous solutioncomprising a hyperbranched polymer or a dendrimer with a terminal thiolfunctional groups where the thiol titre is in the range of 100 to 5000meg/l, said solution have a pH in the range of 5 to 11, and (C) anaqueous solution comprising a thiol present at a concentration of 0.05to 5M, said solution having a pH in the range of from 6.5 to 9, the pHbeing adjusted with a polyquaternary ammonium hydroxide; said reducingfurther comprising contacting said hair fibres with said aqueousreducing agent for 1 to 30 minutes when said reducing agent is saidhydride, or for 30 seconds to 1 hour when said reducing agent is saidhyperbranohed polymer or dendrimer, such that said reducing agentgenerates reactive sites only on the surface of said keratin fibres to adepth of less than 10 μm; (ii) covalently fixing at least one colorant,sunscreen, shine agent or a hydrophobic reactive compound selected fromthe group consisting of a C₈-C₃₀ fatty chain methacrylate, a C₈-C₃₀fatty chain acrylate and a C₂-C₁₈ perfluorinated compound, on saidreactive sites formed on the surface of said keratin fibres.
 18. Themethod of claim 17 wherein said hydride is sodium borohydride orpotassium borohydride.
 19. The method of claim 17 wherein saidhyperbranched polymer or dendrimer is a compound of the followingformula (I)

wherein: Y is an oxygen atom or NH group; A is a linear, branched orcyclic, saturated or unsaturated C₁-C₁₂ alkane di-yl group, said alkanedi-yl group being optionally interrupted by at least one heteroatom,said alkane di-yl further being optionally substituted by an amino,acylamino, carboxylic acid or ester group; and X is a nucleophilicgroup.
 20. Method according to claim 17, wherein in a first step, thedisulphide bonds of the keratin are reduced and then in a second step,after optional rinsing with water the at least one colorant, sunscreen,shine agent or hydrophobic compound is covalently fixed on said reactivesites formed on the surface of said keratin fibres.
 21. Method accordingto claim 17, wherein the reduction of the disulphide bonds of thekeratin is carried out simultaneously with fixing of the at least onecolorant, sunscreen, shine agent or hydrophobic compound.
 22. Methodaccording to claim 17, wherein the reduction of the disulphide bonds iscarried out to a depth of about 4 to 5 μm.
 23. Method according to claim17, wherein the reduction is carried out to generate 0.1% to 5% byweight of cysteine with respect to the total amino acids of thekeratinous hair fibres.
 24. Method according to claim 17, whereinreduction is carried out in order to generate 0.1% to 2% by weight ofcysteine with respect to the total amino acids of the keratinous hairfibres.
 25. Method according to claim 17 wherein said pH is in the rangeof 7.5 to 10.5 when said reducing agent is said aqueous solutioncomprising a hyperbranched polymer or a dendrimer.
 26. The method ofclaim 17 wherein said colorant is selected from the group consisting ofCl 61205, Cl 20505, Cl 61200, Cl 17757, Cl 18105, Cl 18972, ReactiveYellow 135 and Cl
 18200. 27. The method according to claim 17 whereinthe temperature of the aqueous reducing agent solution is in the rangeof from room temperature to less than 60° C.
 28. The method according toclaim 17, wherein the temperature of the aqueous reducing agent solutionis room temperature.
 29. The method of claim 17 wherein said hydrophobiccompound is selected from the group consisting of octadecylmethacrylate, octadecyl acrylate, hexafluoropropene oxide and methylperfluoro-3-buteneoate.